In FY2017, we continue to explore several population-based datasets to investigate disparities in tobacco use patterns. For example, we expanded our previous research on racial/ethnic differences in susceptibility to cigarette smoking among youth. We applied a time-varying effect modeling technique to the National Youth Tobacco Survey (NYTS) 1999-2014, and found that compared to non-Hispanic White, Hispanic youth have been consistently more susceptible to cigarette smoking, while susceptibility of cigarette smoking itself did not change over time despite reduction in youth smoking. The paper is published in Pediatrics and has drawn attention from several media outlets including NEJM Journal Watch, Reuters, and NBC News. We also examined this research question using the Population Assessment of Tobacco and Health (PATH) Study Wave 1 data, and found that Hispanic, and non-Hispanic Black youth were more likely than their non-Hispanic White counterpart to be susceptible to tobacco use. Additionally, we applied the Tobacco Product Use Patterns (T-PUP) model developed by our team to the NYTS 1999-2014 data. We discovered that while the proportion of youth who use cigarettes exclusively has declined over time, an increasing proportion of youth reported exclusively using non-cigarettes combustible and exclusively using non-combustible tobacco products. This group surpassed those exclusively using cigarettes in 2010. The prevalence of poly-tobacco products was also on the rise. Furthermore, we documented the trends in awareness, use of, and beliefs about electronic cigarettes and snus. We found that, using the data from the Minnesota Adolescent Community Cohort (MACC) Study, young adults from the Midwest were increasing aware of these products, but the beliefs and use patterns differed between these two products. We expanded the T-PUP model we previously developed by examining the variations in tobacco product consumption, and nicotine and tobacco-specific nitrosamines (TSNAs) exposure by T-PUP. Using data from the National Health And Nutrition Examination Survey 1999-2012, we found that, among adult tobacco users, dual and poly-tobacco product users did not always have lower product consumption compared to exclusive product users. We also found that dual and poly-tobacco product users, in some cases, had higher nicotine and TSNAs exposure than exclusive product users. This will inform how we examine health risks associated with dual and poly-tobacco product use in the future. We also investigated risk factors associated with tobacco use. For example, after analyzing the data from the Florida Youth Tobacco Survey, we found that youth who lived with e-cigarette users, who used e-cigarette themselves, and who were exposed to e-cigarette advertising were more likely than those who did not live with e-cigarette users, who did not use e-cigarettes, and who were not exposed to e-cigarette advertising to think the cigarette smoking is an acceptable behavior. Findings from this study were reported by Reuters. We continued to examine the role of tobacco marketing on tobacco use and disparities. For example, in both the MACC Study and PATH Study, we found that lower socio-economic status was associated with higher exposure to tobacco direct mail marketing. In the MACC Study, we also found that receipt of snus coupons was associated with susceptibility to snus use, while in the PATH Study, we found that receipt of tobacco direct mail coupons was associated with progression and continuation of cigarette smoking. Together with the PATH Study Team, we found that engagement with online tobacco marketing was associated with susceptibility to tobacco use among US youth. Lastly, we examined the impact of tobacco control policies on tobacco use and its disparities. Using the Minnesota Adult Tobacco Survey (MATS) data, we found that a cigarette tax increase changed how smokers manage their cigarette expenditure by engaging in different cigarette expenditure minimizing behaviors. Changes in the engagement with these behaviors also differed by socio-economic status. Moreover, lower socioeconomic status smokers were more likely to engage in smoking cessation behaviors compared to higher socioeconomic status smokers, illustrating the ability of cigarette excise taxes to reduce tobacco use disparities. To examine the potential impact of implementing a cigarette price promotion ban, we examined the International Tobacco Control Project and compared the exposure to and influence of tobacco price promotions between countries with and without a price promotion ban. We found that exposure to tobacco price promotions was less prevalent in countries with a price promotion ban compared to countries without such a ban. We also found an association between exposure to price promotions and cigarette smoking only in countries without a price promotion ban, but not in countries with a price promotion ban. Our team has 14 publications and made 16 presentations at various scientific conferences in FY2017.